WEB: Attempt to implement language switcher functionality

For some reason the language switching is working one click behind.
The goal is to have the page switched instantly, but it doesn't happen now.

.htaccess

@@ -5,6 +5,10 @@ RewriteEngine On
 # NOTE: When debugging locally, set this to the directory the site is in
 RewriteBase /
 
+# Fetch language and put it into Cookie
+RewriteCond     %{QUERY_STRING}                                             lang=(.*)?
+RewriteRule     .*                                                           -  [CO=lang:%1:.scummvm.org]
+
 ##
 # Images linked directly from the wiki need to work
 ##
@@ -33,7 +37,7 @@ RewriteRule	^(.+)\.php$														$1/? [NS,R=301]
 # Basic rewrite
 ##
 RewriteRule		^([a-z]+)/?$												?p=$1
- 
+
 ##
 # Compatibility
 ##
@@ -49,7 +53,7 @@ RewriteRule		^(documentation)(/([^/]+))?/? 								?p=$1&d=$3 [L]
 ##
 RewriteRule		^(feeds)/(atom|rss)/?										?p=$1&f=$2 [L]
 
-## 
+##
 # News
 ##
 RewriteRule		^(news)(/([0-9]{8}[a-z]?|archive))?/?$							?p=$1&d=$3 [L]

include/Controller.php

@@ -28,13 +28,6 @@ public function __construct() {
 		global $Smarty;
 		$Smarty = $this->_smarty;
 
-		/**
-		 * Multilanguage suppot
-		 */
-		if (empty($_SESSION['lang']) || !empty($_GET['lang'])) {
-		  $_SESSION['lang'] = empty($_GET['lang']) ? '' : $_GET['lang'];
-		}
-
 		global $lang;
 
 		$this->_smarty->template_dir = array("templates_$lang", 'templates');
@@ -85,12 +78,17 @@ public function __construct() {
 		if (!ExceptionHandler::skipMenus()) {
 			$menus = MenuModel::getAllMenus();
 		}
+
+		# Construct lang URL
+		$pageurl = preg_replace('/\?lang=[a-z]*$/', '', $_SERVER['REQUEST_URI']);
+
 		/* Set up the common variables before displaying. */
 		$vars = array(
 			'release' => RELEASE,
 			'baseurl' => URL_BASE,
 			'heroes_num' => HEROES_NUM,
 			'menus' => $menus,
+			'pageurl' => $pageurl,
 		);
 		$this->_smarty->assign($vars);
 	}

index.php

@@ -1,4 +1,19 @@
 <?php
+
+global $lang;
+
+/**
+ * Multilanguage suppot
+ */
+if (empty($_SESSION['lang']) || !empty($_GET['lang'])) {
+  $_SESSION['lang'] = empty($_GET['lang']) ? '' : $_GET['lang'];
+}
+if (empty($_SESSION['lang']) || !empty($_COOKIE['lang'])) {
+  $_SESSION['lang'] = empty($_COOKIE['lang']) ? '' : $_COOKIE['lang'];
+}
+
+$lang = $_SESSION['lang'];
+
 /* Load the configuration. */
 require_once('include/config.inc.php');
 /* Set up the include path. */

templates/lang_menu.tpl

@@ -3,9 +3,9 @@
         <ul id="langmenu">
             <li><a href="">Language</a>
                 <ul>
-                    <li><a href="?lang="><code class="text-badge">EN</code>English</a></li>
-                    <li><a href="?lang=de"><code class="text-badge">DE</code>German</a></li>
-                    <li><a href="?lang=ru"><code class="text-badge">RU</code>Russian</a></li>
+                    <li><a href="{$pageurl}?lang="><code class="text-badge">EN</code>English</a></li>
+                    <li><a href="{$pageurl}?lang=de"><code class="text-badge">DE</code>German</a></li>
+                    <li><a href="{$pageurl}?lang=ru"><code class="text-badge">RU</code>Russian</a></li>
                 </ul>
             </li>
         </ul>